Fig. 12.4. The principle of a lead system detecting the magnetic dipole moment of a volume source.
(A) The three orthogonal bipolar coils.
(B) The three components of the reciprocal magnetic field _LM in the center of the bipolar coil system.
The region where the coils produce linear reciprocal magnetic fields is rather small and therefore Figures 12.4A and 12.4B are not to scale.